The liquid ejection apparatus is an apparatus including a liquid ejection head, and configured to eject any of various kinds of liquids from this ejection head. As such liquid ejection apparatuses, there are image recording apparatuses such as an inkjet type printer and an inkjet type plotter, for example. Besides, nowadays, with an advantageous feature of the ability to land a very small volume of liquid drop onto a predetermined position precisely, liquid ejection apparatuses of this type have been also applied to various kinds of manufacture apparatuses. For example, the liquid ejection apparatuses are applied to a display manufacture apparatus that manufactures color filters for liquid crystal displays and the like, an electrode formation apparatus that forms electrodes for organic electro luminescence (EL) displays and field emission displays (FED), and a chip manufacture apparatus that manufactures biochips.
As an electronic device used in the liquid ejection head, there is one in which multiple plate-shaped structures (plates) are stacked and bonded together with an adhesive agent. These stacked structures are provided with a liquid passage that communicates with nozzles, and movable regions each of which applies a pressure change to liquid inside the liquid passage and thereby ejects the liquid from the corresponding nozzle. Heretofore, these structures have been bonded to each other with, for example, an epoxy-based adhesive agent. The epoxy-based adhesive agent, however, tends to relatively largely change in viscosity with a temperature change. For this reason, the adhesive agent between structures may flow out into the liquid passage side during heating and pressure application for curing the adhesive agent. Then, as illustrated in FIG. 11, the flowed-out adhesive agent 76 may further flow along a corner angle portion or any other portion of the passage 75 to reach the movable region 77, and then be cured on the movable region 77. In this case, the cured adhesive agent may inhibit driving and displacement of the movable region 77, and therefore adversely affect the liquid ejection. On the other hand, in the case of using an adhesive agent having a relatively high viscosity, the adhesive agent tends to become uneven in thickness when the adhesive agent is spread out thinly, and also has a risk that the structures are bonded insufficiently in some portions, and the liquid may leak from the insufficiently-bonded portions. In a configuration in which passages and so on are formed at higher density to meet the requirement of downscaling of the liquid ejection head, in particular, problems such as the aforementioned ones are more likely to occur because the regions joined with the adhesive agent are also narrow.
To address this, PTL 1 has proposed the invention in which a TiW thin film as a removable thin film is formed on portions where it is desired to avoid the adhesion of the adhesive agent, i.e., corner angle portions formed by the movable regions and the adjacent wall portions, and then the removable thin film is removed after the structures are bonded together, so that no adhesive agent remains on these portions.